1. Field of Invention
The present invention relates to a metal product having improved lustre after painting, and to methods for its production. It is particularly concerned with cold rolled sheet metal, to which special reference will be made in the following description, but it can equally be applied to other types of metal products to be painted.
2. Description of Prior Art
It is known that in order to achieve optimum lustre after painting, sheet metal of this type should ideally have a perfectly smooth and flat surface similar to the surface of a mirror. It also known that other operations, for example shaping by deep drawing, require the sheet metal to have a certain roughness, to provide inter alia adequate lubrication in order to avoid seizing.
At present, these sheet metals have a roughness made up of alternating peaks and valleys, imparted to them by the rolls in the final cold rolling stand. This relatively uniform roughness generally leads to adequate behaviour of the sheet metal during shaping operations. However, it does not allow one to achieve increased lustre of the sheet metal after painting.